Disordered molecular sieve supports for the selective catalytic reduction of NOx

ABSTRACT

A catalyst for selective catalytic reduction of NO x  having one or more transition metals selected from Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir, Pt, and mixtures thereof supported on a support, wherein the support has a molecular sieve having at least one intergrowth phase having at least two different small-pore, three-dimensional framework structures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International Application No.PCT/US2011/028123, filed Mar. 11, 2011, and claims priority of U.S.Provisional Application No. 61/312,832, filed Mar. 11, 2010, thedisclosures of both of which are incorporated herein by reference intheir entireties for all purposes.

FIELD OF THE INVENTION

The present invention relates to supports used for catalysts inselective catalytic reduction.

BACKGROUND OF THE INVENTION

Selective catalytic reduction (SCR) of NO_(x) by nitrogenous compounds,such as ammonia or urea, has developed for numerous applicationsincluding for treating industrial stationary applications, thermal powerplants, gas turbines, coal-fired power plants, plant and refineryheaters and boilers in the chemical processing industry, furnaces, cokeovens, municipal waste plants and incinerators, and a number ofvehicular (mobile) applications, e.g., for treating diesel exhaust gas.

Several chemical reactions occur in an NH₃ SCR system, all of whichrepresent desirable reactions that reduce NO_(x) to nitrogen. Thedominant reaction is represented by reaction (1).4NO+4NH₃+O₂→4N₂+6H₂O  (1)

Competing, non-selective reactions with oxygen can produce secondaryemissions or may unproductively consume ammonia. One such non-selectivereaction is the complete oxidation of ammonia, shown in reaction (2).4NH₃+5O₂→4NO+6H₂O  (2)Also, side reactions may lead to undesirable products such as N₂O, asrepresented by reaction (3).4NH₃+4NO+3O₂→4N₂O+6H₂O  (3)

Catalysts for SCR of NO_(x) with NH₃ may include, for example,aluminosilicate molecular sieves. One application is to control NO_(x)emissions from vehicular diesel engines with the reductant obtainablefrom an ammonia precursor, such as urea, or by injecting ammonia per se.To promote the catalytic activity, transition metals may be incorporatedinto the aluminosilicate molecular sieves. The most commonly testedtransition metal molecular sieves are Cu/ZSM-5, Cu/Beta, Fe/ZSM-5 andFe/Beta because they have a relatively wide temperature activity window.

WO 2008/132452 discloses a method of converting nitrogen oxides in a gasto nitrogen by contacting the nitrogen oxides with a nitrogenousreducing agent in the presence of a molecular sieve catalyst containingat least one transition metal. The molecular sieve is a small porezeolite containing a maximum ring size of eight tetrahedral atoms,wherein the at least one transition metal is selected from the groupconsisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag,In, Sn, Re, Ir and Pt.

SUMMARY OF THE INVENTION

Disordered molecular sieve supported transition metal catalysts mayexhibit improved NH₃-SCR activity along with good thermal andhydrothermal stability. The catalysts may also tolerate repeatedlean/rich high temperature aging. In certain applications, the support(i.e., molecular sieve) per se also demonstrates catalytic activity.Thus, the term “catalyst” is not limited to the metal component ofcompositions described herein.

According to one embodiment of the present invention, a catalyst forselective catalytic reduction of NO_(x) comprises one or more transitionmetals selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu,Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir, Pt, and mixtures thereofsupported on a support. The support comprises a molecular sieve havingat least one disorder.

According to another embodiment of the present invention, a catalyst forselective catalytic reduction of NO_(x) comprises one or more transitionmetals selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu,Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir, Pt, and mixtures thereof anda support. The support comprises a molecular sieve comprising at leasttwo different framework structures and at least one intergrown phase ofthe at least two different framework structures.

According to another embodiment of the present invention, a catalyst forselective catalytic reduction of NO_(x) comprises one or more transitionmetals selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu,Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir, Pt, and mixtures thereofsupported on a molecular sieve which comprises an intergrown crystal ofat least two different framework structures.

According to another embodiment of the present invention, a method forreducing NO_(x) in a gas comprises exposing the gas having at least onereactant, such as NO_(x), to a catalyst. The catalyst comprises one ormore transition metals supported on a support, wherein the supportcomprises an intergrowth of at least two different framework structures.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more fully understood, reference ismade to the following figures by way of illustration only, in which:

FIG. 1 is a graph illustrating NO_(x) conversion based on temperature ofpure molecular sieve supported copper catalysts (Cu/SAPO-34 andCu/SAPO-18, respectively);

FIG. 2 is a graph illustrating NO_(x) conversion based on temperature ofcopper exchanged pure molecular sieve supports SAPO-18, SAPO-34, andzeolite β, respectively, following calcination;

FIG. 3 is a graph illustrating NO_(x) conversion based on temperature ofcopper exchanged pure molecular sieve supports SAPO-18, SAPO-34, andzeolite β, respectively, following hydrothermal aging;

FIG. 4 is a graph illustrating DIFFaX simulation of AEI/CHA end membersand intergrowth AEI/CHA;

FIG. 5 is a graph illustrating the simulated diffraction produced byDIFFaX and the intergrowth AEI-CHA material;

FIG. 6 is a graph illustrating the intergrowth AEI-CHA is characterizedby the absence of any peak in the 9.8°-12.0° 2θ;

FIG. 7 is a graph illustrating the intergrowth AEI-CHA is characterizedby the absence of a broad peak centered at 16.9° 2θ;

FIG. 8 is a graph illustrating that the intergrowth AEI/CHA in a 10/90mole ratio is also distinguished by the presence of a broad peakcentered at 17.9° 2θ; and

FIG. 9 is a graph illustrating that AEI/CHA intergrowths show improvedperformance over CHA aluminosilicates in Cu SCR formulations following700° C./72 h hydrothermal aging.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention include catalysts, the molecular sievesupports selected for the catalysts, and the use of the catalysts inselective catalytic reduction of NO_(x).

According to one embodiment of the present invention, a catalyst forselective catalytic reduction of NO_(x) comprises one or more transitionmetals selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu,Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir, Pt, and mixtures thereofsupported on a support, wherein the support comprises a molecular sievehaving at least one disorder.

Molecular sieves are well-known to those skilled in the art. As is usedherein “molecular sieve” is understood to mean a metastable materialcontaining pores of a precise and uniform size that may be used as anadsorbent for gases or liquids. The molecules which are small enough topass through the pores are adsorbed while the larger molecules are not.The molecular sieve framework may be defined as is generally acceptableby the International Zeolite Association (IZA) Framework Type Codes (athttp://www.iza-online.org/). The framework type describes the molecularsieve or zeolite structure including its arrangement of cages, thedimensionality of a channel system, and the approximate size of poreopenings. The composition, the geometry of the framework, and the numberand the nature of defects are also relevant. The pore size of themolecular sieves may be defined by the member rings as follows: largepore rings are 12-member rings or larger; medium pore rings are10-member rings; and small pore rings are 9-member rings or smaller.Preferably, small pore rings have 8-member rings or smaller.

It will be appreciated that by defining the molecular sieve by itsFramework Type Code (FTC), the “Type Material” (e.g., the species firstused to establish the framework type) and any and all isotypic frameworkmaterials are included. Use of a FTC herein is intended to refer to theType Material and all isotypic framework materials defined by that FTC.The distinction between molecular sieve type materials, such asnaturally occurring (i.e. mineral), and isotypes within the sameFramework Type Code may reflect differences in the properties betweenthe materials, for example, which may be evident during use in selectivecatalytic reduction.

Molecular sieves for use in the present application include natural andsynthetic molecular sieves. It may be preferable to use syntheticmolecular sieves because the molecular sieves may have a more uniformsilica-to-alumina ratio (SAR), crystallite size, crystallite morphology,and the absence of impurities (e.g. alkaline earth metals).

Molecular sieves may be ordered or disordered. Ordered molecular sieves(e.g., regular crystalline solids) are crystal structures which areperiodically ordered in 3-dimensions. Ordered molecular sieves may alsobe considered “pure” molecular sieves. These structures are classifiedbased on their repeating periodic building units (PerBUs) and may betermed “end-member structures” if periodic ordering occurs in all threedimensions. Disordered molecular sieves, on the other hand, showperiodic ordering in dimensions less than 3, e.g., 0, 1, or 2dimensions. In disordered structures, the stacking sequence of thePerBUs deviates from periodic ordering. This may also be explained as astructural or stacking disorder of structurally invariant PerBUs. Thesupports used for the catalysts of the present invention comprise amolecular sieve having at least one disorder or defect. In other words,the molecular sieve is a disordered structure and does not have periodicordering in all three dimensions.

The selected molecular sieve may have a defect or disorder including,but not limited to, stacking disorders, planar faults, and intergrowthof phases. In a layered structure with a stacking disorder, a singleframework type may deviate from periodic ordering. A planar fault in theframework structure may include, for example, structures on either sideof the plane which are mirror images (e.g., a “twin plane” phenomenon)or rotation of one part of a crystal, on a specific plane, with respectto another. An intergrowth of phases may include a transition from oneframework structure to another framework structure. Thus, the molecularsieve may include any one or more types of defects or disorders leadingto any known or unknown disordered framework. Known disorderedframeworks include, for example, ABC-6, AEI/CHA, AEI/SAV, AEN/UEI,AFS/BPH, BEC/ISV, beta, fuajasite, ITE/RTH, KFI/SAV, lovdarite,montesommaite, MTT/TON, pentasils, SBS/SBT, SSF/STF, SSZ-33, and ZSM-48.The molecular sieves disclosed herein may be obtained or prepared fromany suitable source known in the art.

In the case of regular AEI and CHA framework type molecular sieves, forexample, the periodic building unit is a double six ring layer. Thereare two types of layers “a” and “b”, which are topologically identicalexcept “b” is the mirror image of “a”. When layers of the same typestack on top of one another, i.e. aaaaaaaa or bbbbbbbb, the frameworktype CHA is generated. When layers “a” and “b” alternate, i.e.,abababab, the framework type AEI is generated. Intergrown AEI-CHAmolecular sieves may comprise regions of CHA framework sequences andregions of AEI framework sequences. Each change from a CHA to an AEIframework type sequence results in a stacking fault, an example of adisorder. In addition, stacking faults can occur in a pure CHA phasematerial when a sequence of one mirror image layers intersects asequence of the opposite mirror image layers, such as for example inaaaaaabbbbbbb.

In an exemplary embodiment, the disorder of the molecular sieve is anintergrowth of two phases of at least two different frameworkstructures. In other words, a single intergrown crystal may comprise atleast two different framework structures. Intergrown molecular sievephases may be disordered planar intergrowths of molecular sieveframeworks. The two different framework structures may include, forexample, a mixed phase of one or more of AEI/CHA, AEI/SAV, AEN/UEI,AFS/BPH, BEC/ISV, ITE/RTH, KFI/SAV, IMTT/TON, SBS/SBT, and SSF/STF.

In one embodiment of the present invention, a catalyst for selectivecatalytic reduction of NO_(x) comprises one or more transition metalsand a support, wherein the support comprises a molecular sievecomprising at least one intergrown phase of at least two differentframework structures. An intergrown phase may include an area of thecrystal where one framework structure is transitioned into a differentframework structure. In other words, the intergrown phase may be a partof the crystal structure which serves to complete both types offrameworks. Thus, the molecular sieve may include one or moreintergrowth regions with two or more framework structures throughout thesupport.

In an exemplary embodiment, the framework structure is a small poremolecular sieve. A small pore molecular sieve may be defined as having amaximum ring size of nine tetrahedral atoms. In a preferred embodiment,the at least two different framework structures are both small poremolecular sieves. Similarly, if there are more than two frameworkstructures, all may be small pore molecular sieves. Illustrativeexamples of suitable small pore molecular sieves are set out in Table 1.

TABLE 1 Small Pore Molecular Sieves Molecular Sieve Frame- work Type (byFrame- Type material* and Di- work illustrative isotypic men- Typeframework sion- Pore size Additional Code) structures ality (A) info ACO*ACP-1 3D 3.5 × 2.8, Ring sizes- 3.5 × 3.5 8, 4 AEI *AlPO-18 3D 3.8 ×3.8 Ring sizes- 8, 6, 4 [Co—Al—P—O]-AEI SAPO-18 SIZ-8 SSZ-39 AEN*AlPO-EN3 2D 4.3 × 3.1, Ring sizes- 2.7 × 5.0 8, 6, 4 AlPO-53(A)AlPO-53(B) [Ga—P—O]-AEN CFSAPO-1A CoIST-2 IST-2 JDF-2 MCS-1 MnAPO-14Mu-10 UiO-12-500 UiO-12-as AFN *AlPO-14 3D 1.9 × 4.6, Ring sizes- 2.1 ×4.9, 8, 6, 4 3.3 × 4.0 |(C₃N₂H₁₂)—|[Mn—Al— P—O]-AFN GaPO-14 AFT *AlPO-523D 3.8 × 3.2, Ring sizes- 3.8 × 3.6 8, 6, 4 AFX *SAPO-56 3D 3.4 × 3.6Ring sizes- 8, 6, 4 MAPSO-56, M = CO, Mn, Zr SSZ-16 ANA *Analcime 3D 4.2× 1.6 Ring sizes- 8, 6, 4 AlPO₄-pollucite AlPO-24 Ammonioleucite[Al—Co—P—O]-ANA [Al—Si—P—O]-ANA |Cs—|[Al—Ge—O]-ANA |Cs—|[Be—Si—O]-ANA|Cs₁₆|[Cu₈Si₄₀O₉₆]-ANA |Cs—Fe|[Si—O]-ANA |Cs—Na—(H₂O)|[Ga— Si—O]-ANA[Ga—Ge—O]-ANA |K—|[B—Si—O]-ANA |K—|[Be—B—P—O]-ANA |Li—|[Li—Zn—Si—O]-ANA|Li—Na|[Al—Si—O]-ANA |Na—|[Be—B—P—O]-ANA |(NH₄)—|[Be—B—P— O]-ANA|(NH₄)—|[Zn—Ga—P— O]-ANA [Zn—As—O]-ANA Ca—D Hsianghualite Leucite Na—BPollucite Wairakite APC *AlPO—C 2D 3.7 × 3.4, Ring sizes- 4.7 × 2.0 8,6, 4 AlPO-H3 CoAPO-H3 APD *AlPO-D 2D 6.0 × 2.3, Ring sizes- 5.8 × 1.3 8,6, 4 APO-CJ3 ATT *AlPO-12-TAMU 2D 4.6 × 4.2, Ring sizes- 3.8 × 3.8 8, 6,4 AlPO-33 RMA-3 CDO *CDS-1 2D 4.7 × 3.1, Ring sizes- 4.2 × 2.5 8, 5MCM-65 UZM-25 CHA *Chabazite 3D 3.8 × 3.8 Ring sizes- 8, 6, 4 AlPO-24[Al—As—O]-CHA [Al—Co—P—O]-CHA |Co|[Be—P—O]-CHA |Co₃(C₆N₄H₂₄)₃(H₂O)₉|[Be₁₈P₁₈O₇₂]-CHA [Co—Al—P—O]-CHA |Li—Na|[Al—Si—O]-CHA[Mg—Al—P—O]-CHA [Si—O]—CHA [Zn—Al—P—O]-CHA [Zn—As—O]-CHA CoAPO-44CoAPO-47 DAF-5 GaPO-24 K-Chabazite Linde D Linde R LZ-218 MeAPO-47MeAPSO-47 (Ni(deta)₂)-UT-6 Phi SAPO-34 SAPO-47 SSZ-13 UiO-21Willhendersonite ZK-14 ZYT-6 CHI Chiavennite 1D 3.9 × 4.3 DDR*Deca-dodecasil 3R 2D 4.4 × 3.6 Ring sizes- 8, 6, 5, 4 [B—Si—O]-DDRSigma-1 ZSM-58 DFT *DAF-2 3D 4.1 × 4.1, Ring sizes- 4.7 × 1.8 8, 6, 4ACP-3, [Co—Al—P— O]-DFT [Fe—Zn—P—O]-DFT [Zn—Co—P—O]-DFT UCSB-3GaGeUCSB-3ZnAs UiO-20, [Mg—P—O]-DFT EAB *TMA-E 2D 5.1 × 3.7 Ring sizes- 8,6, 4 Bellbergite EDI *Edingtonite 3D 2.8 × 3.8, Ring sizes- 3.1 × 2.0 8,4 |(C₃H₁₂N₂)_(2.5)| [Zn₅P₅O₂₀]-EDI [Co—Al—P—O]-EDI [Co—Ga—P—O]-EDI|Li—|[Al—Si—O]-EDI |Rb₇Na(H₂O)₃| [Ga₈Si₁₂O₄₀]-EDI [Zn—As—O]-EDI K—FLinde F Zeolite N EPI *Epistilbite 2D 4.5 × 3.7, Ring sizes- 3.6 × 3.68, 4 ERI *Erionite 3D 3.6 × 5.1 Ring sizes- 8, 6, 4 AlPO-17 Linde TLZ-220 SAPO-17 ZSM-34 GIS *Gismondine 3D 4.5 × 3.1, Ring sizes- 4.8 ×2.8 8, 4 Amicite [Al—Co—P—O]-GIS [Al—Ge—O]-GIS [Al—P—O]-GIS [Be—P—O]-GIS|(C₃H₁₂N₂)₄| [Be₈P₈O₃₂]-GIS |(C₃H₁₂N₂)₄| [Zn₈P₈O₃₂]-GIS [Co—Al—P—O]-GIS[Co—Ga—P—O]-GIS [Co—P—O]-GIS |Cs₄|[Zn₄B₄P₈O₃₂]-GIS [Ga—Si—O]-GIS[Mg—Al—P—O]-GIS |(NH₄)₄|[Zn₄B₄P₈O₃₂]-GIS |Rb₄|[Zn₄B₄P₈O₃₂]-GIS[Zn—Al—As—O]-GIS [Zn—Co—B—P—O]-GIS [Zn—Ga—As—O]-GIS [Zn—Ga—P—O]-GISGarronite Gobbinsite MAPO-43 MAPSO-43 Na-P1 Na-P2 SAPO-43 TMA-gismondineGOO *Goosecreekite 3D 2.8 × 4.0, Ring sizes- 2.7 × 4.1, 8, 6, 4 4.7 ×2.9 IHW *ITQ-32 2D 3.5 × 4.3 Ring sizes- 8, 6, 5, 4 ITE *ITQ-3 2D 4.3 ×3.8, Ring sizes- 2.7 × 5.8 8, 6, 5, 4 Mu-14 SSZ-36 ITW *ITQ-12 2D 5.4 ×2.4, Ring sizes- 3.9 × 4.2 8, 6, 5, 4 LEV *Levyne 2D 3.6 × 4.8 Ringsizes- 8, 6, 4 AlPO-35 CoDAF-4 LZ-132 NU-3 RUB-1 [B—Si—O]-LEV SAPO-35ZK-20 ZnAPO-35 KFI ZK-5 3D 3.9 × 3.9 Ring sizes- 8, 6, 4 |18-crown-6|[Al—Si—O]-KFI [Zn—Ga—As—O]-KFI (Cs,K)-ZK-5 P Q LOV Lovdarite 3D 3.2 ×4.5, Ring sizes- 3.0 × 4.2, 9, 8 3.6 × 3.7 MER *Merlinoite 3D 3.5 × 3.1,Ring sizes- 3.6 × 2.7, 8,4 5.1 × 3.4, 3.3 × 3.3 [Al—Co—P—O]-MER|Ba—|[Al—Si—O]-MER |Ba—Cl—| [Al—Si—O]-MER [Ga—Al—Si—O]-MER|K—|[Al—Si—O]-MER |NH₄—|[Be—P—O]-MER K-M Linde W Zeolite W MON*Montesommaite 2D 4.4 × 3.2, Ring sizes- 3.6 × 3.6 8, 5, 4 [Al—Ge—O]-MONNAB Babesite 2D 2.7 × 4.1, 3.0 × 4.6 NAT Natrolite 3D 2.6 × 3.9, Ringsizes- 2.5 × 4.1 9, 8 NSI *Nu-6(2) 2D 2.6 × 4.5, Ring sizes- 2.4 × 4.88, 6, 5 EU-20 OWE *UiO-28 2D 4.0 × 3.5, Ring sizes- 4.8 × 3.2 8, 6, 4ACP-2 PAU *Paulingite 3D 3.6 × 3.6 Ring sizes- 8, 6, 4 [Ga—Si—O]-PAUECR-18 PHI *Phillipsite 3D 3.8 × 3.8, Ring sizes- 3.0 × 4.3, 8, 4 3.3 ×3.2 [Al—Co—P—O]-PHI DAF-8 Harmotome Wellsite ZK-19 RHO *Rho 3D 3.6 × 3.6Ring sizes- 8, 6, 4 [Be—As—O]-RHO [Be—P—O]-RHO [Co—Al—P—O]-RHO|H—|[Al—Si—O]-RHO [Mg—Al—P—O]-RHO [Mn—Al—P—O]-RHO |Na₁₆Cs₈|[Al₂₄Ge₂₄O₉₆]—RHO |NH₄—|[Al—Si—O]-RHO |Rb—|[Be—As—O]-RHO GallosilicateECR-10 LZ-214 Pahasapaite RSN RUB-17 3D 3.3 × 4.4, Ring sizes- 3.1 ×4.3, 9, 8 3.4 × 4.1 RTH *RUB-13 2D 4.1 × 3.8, Ring sizes- 5.6 × 2.5 8,6, 5, 4 SSZ-36 SSZ-50 SAT *STA-2 3D 5.5 × 3.0 Ring sizes- 8, 6, 4 SAV*Mg-STA-7 3D 3.8 × 3.8, Ring sizes- 3.9 × 3.9 8, 6, 4 Co-STA-7 Zn-STA-7SBN *UCSB-9 3D TBC Ring sizes- 8, 4, 3 SU-46 SIV *SIZ-7 3D 3.5 × 3.9,Ring sizes- 3.7 × 3.8, 8, 4 3.8 × 3.9 STT SSZ-23 2D 3.7 × 5.3, Ringsizes- 2.4 × 3.5 8, 7 THO *Thomsonite 3D 2.3 × 3.9, Ring sizes- 4.0 ×2.2, 8, 4 3.0 × 2.2 [Al—Co—P—O]-THO [Ga—Co—P—O]-THO|Rb₂₀|[Ga₂₀Ge₂₀O₈₀]-THO [Zn—Al—As—O]-THO [Zn—P—O]-THO [Ga—Si—O]-THO)[Zn—Co—P—O]-THO TSC *Tschörtnerite 3D 4.2 × 4.2, Ring sizes- 5.6 × 3.18, 6, 4 UEI *Mu-18 2D 3.5 × 4.6, Ring sizes- 3.6 × 2.5 8, 6, 4 UFI*UZM-5 2D 3.6 × 4.4, Ring sizes- 3.2 × 3.2 8, 6, 4 (cage) VNI *VPI-9 3D3.5 × 3.6, Ring sizes- 3.1 × 4.0 8, 5, 4, 3 VSN VPI-7 3D 3.3 × 4.3, Ringsizes- 2.9 × 4.2, 9, 8 2.1 × 2.7 YUG *Yugawarlite 2D 2.8 × 3.6, Ringsizes- 3.1 × 5.0 8, 5, 4 Sr-Q ZON *ZAPO-M1 2D 2.5 × 5.1, Ring sizes- 3.7× 4.4 8, 6, 4 GaPO-DAB-2 UiO-7

Molecular sieves with application in the present invention can includethose that have been treated to improve hydrothermal stability.Illustrative methods of improving hydrothermal stability include:

(i) Dealumination by: steaming and acid extraction using an acid orcomplexing agent e.g., EDTA—ethylenediaminetetracetic acid; treatmentwith acid and/or complexing agent; treatment with a gaseous stream ofSiCl₄ (replaces Al in the molecular sieve framework with Si);

(ii) Cation exchange—use of multi-valent cations, such as La; and

(iii) Use of phosphorous containing compounds (see e.g., U.S. Pat. No.5,958,818).

The small pore molecular sieves may be phosphorous-containing orphosphorous-free. In one embodiment, at least one of the small poremolecular sieves is a phosphorous-containing molecular sieve. Forexample, one, two, or more of the framework structures in a mixed phasecomposition may be phosphorous-containing. In another embodiment, atleast one of the small pore molecular sieves is a phosphorous-freemolecular sieve. For example, one, two, or more of the frameworkstructures in a mixed phase composition may be phosphorous-free.

In a particular embodiment, the small pore molecular sieve catalysts foruse in the present invention may be selected from the group consistingof aluminosilicate molecular sieves, metal-substituted aluminosilicatemolecular sieves, and aluminophosphate molecular sieves.Aluminophosphate molecular sieves with application in the presentinvention include aluminophosphate (AlPO) molecular sieves, metalsubstituted (MeAlPO) molecular sieves, silico-aluminophosphate (SAPO)molecular sieves, and metal substituted silico-aluminophosphate (MeAPSO)molecular sieves. SAPO molecular sieves may contain a three-dimensionalmicroporous crystal framework structure of [SiO₂], [AlO₂] and [PO₂]corner sharing tetrahedral units. AlPO molecular sieves may includecrystalline microporous oxides, which have an AlPO₄ framework.

As used herein, “MeAPSO” and “MeAlPO” are intended to cover zeotypessubstituted with one or more metals. Suitable substituent metals includeone or more of, without limitation, As, B, Be, Co, Fe, Ga, Ge, Li, Mg,Mn, Zn and Zr. In an exemplary embodiment, at least one of the smallpore molecular sieves is selected from the group consisting ofaluminosilicate molecular sieves, metal-substituted aluminosilicatemolecular sieves, and aluminophosphate molecular sieves.

Small pore aluminosilicate molecular sieves may have a silica-to-aluminaratio (SAR) of from 2 to 300, optionally 4 to 200, and preferably 8 to150. It will be appreciated that higher SAR ratios are preferred toimprove thermal stability but this may negatively affect transitionmetal exchange.

In an exemplary embodiment, one or more of the small pore molecularsieves is selected from the group of Framework Type Codes consisting of:ACO, AEI, AEN, AFN, AFT, AFX, ANA, APC, APD, ATT, CDO, CHA, DDR, DFT,EAB, EDI, EPI, ERI, GIS, GOO, IHW, ITE, ITW, LEV, KFI, MER, MON, NSI,OWE, PAU, PHI, RHO, RTH, SAT, SAV, SIV, THO, TSC, UEI, UFI, VNI, YUG andZON. In a preferred embodiment, one or more of the small pore molecularsieves may comprise a CHA Framework Type Code selected from SAPO-34,AlPO-34, SAPO-47, ZYT-6, CAL-1, SAPO-40, SSZ-62 or SSZ-13 and/or an AEIFramework Type Code of selected from AlPO-18, SAPO-18, SIZ-8, or SSZ-39.

In a preferred embodiment, the catalyst of the present inventioncomprises one or more transition metals selected from the groupconsisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag,In, Sn, Re, Ir, Pt, and mixtures thereof supported on a support, whereinthe support comprises a molecular sieve having at least one intergrowthphase comprising at least two different small-pore, three-dimensionalframework structures. It has been discovered that metal loaded molecularsieves having at least one intergrowth phase comprising at least twodifferent small-pore, three-dimensional framework structures provideexceptionally good NO_(x) reduction performance, for example in SCRapplications, particularly at low temperatures (e.g., below about 350°C., preferably below about 250° C., for example about 150 to about 250°C. or about 200 to about 250° C.). Surprisingly, molecular sievescomprising or consisting of such intergrowths of two differentframeworks perform substantially better than molecular sievesconstructed of either framework alone. For example, a metal loadedmolecular sieve comprising an AEI/CHA intergrowth has significantlyimproved low temperature NO_(x) conversion compared to a metal loadedmolecular sieve having only a CHA framework or having only an AEIframework.

In certain preferred embodiments, the intergrowth comprises at least twodifferent small-pore, three-dimensional framework structures, eachhaving a maximum of eight ring members. In a particularly preferredembodiment, the molecular sieve has at least one intergrowth phasecomprising a first small-pore, three-dimensional framework structure anda second small-pore, three-dimensional framework structure, wherein saidfirst and second frameworks are present in a mole ratio of about 1:99 toabout 99:1. The composition's mole ratio can be determined by analyticaltechniques such as X-ray Diffraction (XRD) analysis.

Examples of preferred intergrowths comprise, or consist essentially of,a first framework structure which is CHA and said second frameworkstructure which is selected from the group consisting of AEI, GME, AFX,AFT, and LEV. Preferred molecular sieves having the abovementionedframeworks include aluminosilicates, silico-aluminophosphates, andcombinations thereof. Particularly preferred molecular sieves comprisesan intergrowth of at least one of SAPO-34, SSZ-13, SAPO-47, CAL-1,SAPO-40, SSZ-62, and ZYT-6, and at least one of AlPO-18, SAPO-18, SIZ-8,SSZ-39, AlPO-52, SAPO-56, SSZ-16, AlPO-35, LZ-132, Nu-3, SAPO-35, ZK-20,and Gmelinite, more preferably intergrowth of at least one of SAPO-34and SSZ-13 and at least one of SAPO-18, SSZ-39, SSZ-16, Nu-3, andGmelinite, such as a SAPO-18/SAPO-34 intergrowth. For embodimentswherein the molecular sieve comprises or consists essentially anSAPO-18/SAPO-34 intergrowth, the two frameworks are preferably presentin a mole ratio of about 1:99 to about 50:50, such as about 1:99 toabout 20:80 or about 5:99 to about 15:85.

In one embodiment, the mixed phase composition is an AEI/CHA-mixed phasecomposition. The mole ratio of each framework type in the molecularsieve is not particularly limited, provided that each framework ispresent in an amount sufficient to improve the NO_(x) performance of thematerial. For example, the mole ratio of AEI/CHA may range from about5/95 to about 95/5, preferably about 60/40 to 40/60. In an exemplaryembodiment, the mole ratio of AEI/CHA may range from about 5/95 to about40/60.

Other examples of preferred intergrowths include CHA/AEI, CHA/GME,CHA/AFX, CHA/AFT, and CHA/LEV. Examples of other framework ratios forthese preferred intergrowths include 1:99, 5:95, 10:90, 15:85, 20:80,25:75, 30:70, 40:60, 50:50, 60:40, 70:30, 75:25, 80:20, 85:15, 90:10,95:5, and 99:1. Thus, the present invention includes intergrowths ofCHA/AEI, CHA/GME, CHA/AFX, CHA/AFT, or CHA/LEV wherein any two of theabovementioned mole ratios serve as boundaries for a framework moleratio range.

It should be noted that the nomenclature used to describe intergrowthsherein does not attribute significance to the order in which differentframeworks appear. For example, CHA/AEI is equivalent to AEI/CHA.However, the ratio of different frameworks within an intergrowth doescorrespond to the order in which the frameworks are names. For example,5:95 AEI/CHA represents an intergrowth having 5% AEI and 95% CHA.

The catalyst comprises one or more transition metals supported on themolecular sieve support. Any suitable transition metal may be selected.Transition metals particularly effective for use during selectivecatalytic reduction include transition metals selected from the groupconsisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag,In, Sn, Re, Ir, Pt, and mixtures thereof. As used herein, the termtransition metal includes Zn, Ga, In, and Sn even though these metalsare not in the d-block of the periodic table. In one embodiment, the oneor more transition metals is selected from the group consisting of Cr,Mn, Fe, Co, Ce, Ni, Cu, Rh, Pd, Pt, and mixtures thereof. Preferably,the transition metal is selected from Cu, Fe, Co, Pt, and Mn. Morepreferably, the one or more transition metals may be selected from thegroup consisting of Fe, Cu, and mixtures thereof. In an exemplaryembodiment, the transition metal is copper. Any suitable and effectiveamount of at least one transition metal may be used in the catalyst. Thetotal amount of the transition metal(s) that may be included in themolecular sieve may be from about 0.01 to 20 wt % based on the totalweight of the catalyst. In one embodiment, the total amount of thetransition metal(s) that may be included may be from about 0.1 to 10 wt%. In a particular embodiment, the total transition metal amount thatmay be included is from about 0.5 to 5 wt %. In another embodiment, theamount of transition metal is from about 0.01 to about 6 weight percent,more preferably about 1 to about 3 weight percent, even more preferablyabout 1.5 to about 2.5 weight percent, based on the total weight of thesupport.

The molecular sieve acts as a support for the transition metal, e.g.,the transition metal may be inside the pore(s) and/or may be on theexternal surface of the molecular sieve. In an exemplary embodiment, asignificant amount of the transition metal(s) resides inside the pores.

The transition metal(s) may also be included in the molecular sieveand/or supported by the molecular sieve using any feasible method. Forexample, the transition metal can be added after the molecular sieve hasbeen synthesized, e.g., by incipient wetness or exchange process; or canbe added during molecular sieve synthesis.

The molecular sieves may be synthesized using any suitable processesknown in the art. Suitable synthesis techniques are explained in U.S.Pat. Nos. 6,334,994, 7,094,389, U.S. Patent Application No.2002/0165089, and PCT Patent Application No. WO2005/063623, all of whichare incorporated herein by reference in their entireties.

The molecular sieve catalysts may be used in any suitable form. Forexample, the molecular sieve catalyst may be used in powder form, asextrudates, as pellets, or in any other suitable form.

The molecular sieve catalysts for use in the present invention may becoated on a suitable substrate monolith or can be formed asextruded-type catalysts, but are preferably used in a catalyst coating.In one embodiment, the molecular sieve catalyst is coated on aflow-through monolith substrate (i.e., a honeycomb monolithic catalystsupport structure with many small, parallel channels running axiallythrough the entire part) or filter monolith substrate, such as awall-flow filter, etc. The molecular sieve catalyst for use in thepresent invention may be coated, e.g., as a washcoat component, on asuitable monolith substrate, such as a metal or ceramic flow throughmonolith substrate or a filtering substrate, such as a wall-flow filteror sintered metal or partial filter (such as those disclosed in WO01/80978 or EP 1057519). Alternatively, the molecular sieves for use inthe present invention may be synthesized directly onto the substrateand/or may be formed into an extruded-type flow through catalyst.

Washcoat compositions containing the molecular sieves for use in thepresent invention for coating onto the monolith substrate formanufacturing extruded type substrate monoliths may comprise a binder,such as alumina, silica, (non molecular sieve) silica-alumina, naturallyoccurring clays, such as TiO₂, ZrO₂, SnO₂, CeO₂, or mixtures thereof.

According to one embodiment of the present invention, a method of usingthe catalyst comprises exposing a catalyst to at least one reactant in achemical process. In other words, a method for reducing NO_(x) in a gascomprises exposing the gas having at least one reactant, such as NO_(x),to a catalyst. As used herein, a chemical process for reducing NO_(x) ina gas can include any suitable chemical process using a catalystcomprising a molecular sieve or zeolite. Typical chemical processesinclude, but are not limited to, exhaust gas treatment such as selectivecatalytic reduction using nitrogenous reductants, lean NO_(x) catalyst,catalyzed soot filter, or a combination of any one of these with aNO_(x) adsorber catalyst or a three-way catalyst (TWC), e.g.,NAC+(downstream)SCR or TWC+(downstream)SCR.

A method of treating NO_(x) in an exhaust gas of a lean burn internalcombustion engine is to store the NO_(x) from a lean gas in a basicmaterial and then to release the NO_(x) from the basic material andreduce it periodically using a rich gas. The combination of a basicmaterial (such as an alkali metal, alkaline earth metal, or a rare earthmetal), and a precious metal (such as platinum), and possibly also areduction catalyst component (such as rhodium) is typically referred toas a NO_(x) adsorber catalyst (NAC), a lean NO_(x) trap (LNT), or aNO_(x) storage/reduction catalyst (NSRC). As used herein, NO_(x)storage/reduction catalyst, NO_(x) trap, and NO_(x) adsorber catalyst(or their acronyms) may be used interchangeably.

Under certain conditions, during the periodically rich regenerationevents, NH₃ may be generated over a NO_(x) adsorber catalyst. Theaddition of a SCR catalyst downstream of the NO_(x) adsorber catalystmay improve the overall system NO_(x) reduction efficiency. In thecombined system, the SCR catalyst is capable of storing the released NH₃from the NAC catalyst during rich regeneration events and utilizes thestored NH₃ to selectively reduce some or all of the NO_(x) that slipsthrough the NAC catalyst during the normal lean operation conditions. Asused herein, such combined systems may be shown as a combination oftheir respective acronyms, e.g., NAC+SCR or LNT+SCR.

The catalysts may be effective in reducing or lean conditions, e.g., asencountered in engine emissions. For example, the lean portion of thecycle may consist of exposure to about 200 ppm NO, 10% O₂, 5% H₂O, 5%CO₂ in N₂, and the rich portion of the cycle may consist of exposure toabout 200 ppm NO, 5000 ppm C₃H₆, 1.3% H₂, 4% CO, 1% O₂, 5% H₂O, 5% CO₂in N₂. A reducing atmosphere is an atmosphere having a lambda value ofless than 1, i.e., the redox composition is net reducing. A leanatmosphere is one having a lambda value of greater than 1, i.e., theredox composition is net oxidizing. The catalysts described herein maybe particularly effective when exposed to a reducing atmosphere, moreparticularly a high temperature reducing atmosphere, such as whenencountered during the rich phase of a lean/rich excursion cycle.

A method for reducing NO_(x) in a gas comprises exposing the gas havingat least one reactant to a catalyst. The reactant may include anyreactants typically encountered in the chemical processes above.Reactants may include a selective catalytic reductant, such as ammonia.Selective catalytic reduction may include (1) using ammonia or anitrogenous reductant or (2) a hydrocarbon reductant (the latter alsoknown as lean NO_(x) catalysis). Other reactants may include nitrogenoxides and oxygen. In an exemplary embodiment, the catalysts describedherein are used during selective catalytic reduction of NO_(x) withammonia.

In one embodiment, the at least one reactant, e.g., nitrogen oxides, isreduced with the reducing agent at a temperature of at least 100° C. Inanother embodiment, the at least one reactant is reduced with thereducing agent at a temperature from about 150° C. to 750° C. In aparticular embodiment, the temperature range is from about 175 to 550°C.

For a reactant including nitrogen oxides, the reduction of nitrogenoxides may be carried out in the presence of oxygen or in the absence ofoxygen. The source of nitrogenous reductant can be ammonia per se,hydrazine, ammonium carbonate, ammonium carbamate, ammonium hydrogencarbonate, ammonium formate or any suitable ammonia precursor, such asurea ((NH₂)₂CO).

The method may be performed on a gas derived from a combustion process,such as from an internal combustion engine (whether mobile orstationary), a gas turbine and coal or oil fired power plants. Themethod may also be used to treat gas from industrial processes such asrefining, from refinery heaters and boilers, furnaces, the chemicalprocessing industry, coke ovens, municipal waste plants andincinerators, coffee roasting plants, etc.

In a particular embodiment, the method is used for treating exhaust gasfrom a vehicular internal combustion engine with a lean/rich cycle, suchas a diesel engine, a gasoline engine, or an engine powered by liquidpetroleum gas or natural gas.

For a reactant including nitrogen oxides, the nitrogenous reductant maybe metered into the flowing exhaust gas only when it is determined thatthe molecular sieve catalyst is capable of catalyzing NO_(x) reductionat or above a desired efficiency, such as at above 100° C., above 150°C., or above 175° C. The determination by the control means can beassisted by one or more suitable sensor inputs indicative of a conditionof the engine selected from the group consisting of: exhaust gastemperature, catalyst bed temperature, accelerator position, mass flowof exhaust gas in the system, manifold vacuum, ignition timing, enginespeed, lambda value of the exhaust gas, the quantity of fuel injected inthe engine, the position of the exhaust gas recirculation (EGR) valveand thereby the amount of EGR and boost pressure.

Metering may be controlled in response to the quantity of nitrogenoxides in the exhaust gas determined either directly (using a suitableNO_(x) sensor) or indirectly, such as using pre-correlated look-uptables or maps—stored in the control means—correlating any one or moreof the abovementioned inputs indicative of a condition of the enginewith predicted NO_(x) content of the exhaust gas.

The disordered molecular sieve supported transition metal catalystsdescribed herein may exhibit improved NH₃-SCR activity, good thermalstability, good hydrothermal stability, and tolerate repeated lean/richhigh temperature aging.

FIGS. 1, 2, and 3 show NO_(x) conversion of different ordered molecularsieve supports SAPO-18, SAPO-34, and zeolite β, with copper as thetransition metal. FIG. 1 shows a comparison of the NH₃ SCR activity ofSAPO-34.Cu and SAPO-18.Cu at different operating temperatures afteraging at 900° C. for 4 hours. FIG. 2 shows a comparison of the NH₃ SCRactivity of SAPO-18.Cu, SAPO-34.Cu, and Beta.Cu at different operatingtemperatures after calcination. The results indicate that SAPO-18 iscomparable to SAPO-34 or Beta.Cu at different operating temperaturesafter calcination. FIG. 3 shows a comparison of the SCR activity ofSAPO-18.Cu, SAPO-34.Cu and Beta.Cu after aging at 900° C. for 4 hours.As is evident, the SAPO-18 supported Cu catalysts exhibited comparableNH₃-SCR activity and thermal durability as a SAPO-34 supported Cucatalysts, but the zeolite β exhibited poor results after hydrothermalaging. Thus, the results show that SAPO-34 and SAPO-18 have excellenthydrothermal durability compared to standard zeolites.

It is envisioned that a disordered molecular sieve, such as AEI/CHA,will be used as the support for one or more transition metals, such ascopper. It is expected that the mixed phase molecular sieve support willexhibit good NO_(x) conversion. In particular, it is envisioned that thecopper-AEI/CHA catalyst will exhibit good NH₃-SCR activity, thermaldurability, and hydrothermal durability.

The entire contents of any and all patents and references cited hereinare incorporated herein by reference.

While preferred embodiments of the invention have been shown anddescribed herein, it will be understood that such embodiments areprovided by way of example only. Numerous variations, changes andsubstitutions will occur to those skilled in the art without departingfrom the spirit of the invention. Accordingly, it is intended that theappended claims cover all such variations as fall within the spirit andscope of the invention.

EXAMPLES

The following non-limiting examples are provided to illustrate certainaspects of the invention.

Example 1 Preparation of Copper-Loaded AEI/CHA Intergrowth MolecularSieves

A sample of a molecular sieve material was obtained and tested todetermine its structure and composition. For the sample, an X-rayDiffraction (XRD) pattern was collected on a PANalytical X'Pert PRO MPD(Multi-Purpose Diffractometer), using a copper K_(α) radiation. Thediffraction pattern was collected using programmable divergence andreceiving slit maintaining a constant sample illuminated area of 10 mmand the x-rays were measured using a Real Time Multiple Strip (RTMS)detector. DIFFaX analysis was used to determine the AEI/CHA intergrowthratio. DIFFaX is a program used to simulated powder diffraction data.The program is available from the International Zeolite Association orfrom the authors Michael M. J. Treacy and Michael W. Dean. The versionused to generate the simulations was DIFFaX 1.813. The input file usedto generate the simulation was the same as detailed in the document WO02/070407. The simulations were generated from 5 to 120° 2θ withinstrumental broadening applied to the output file and a randomdistribution of AEI to CHA layers. The random distribution of layers isused only for comparison to the collected data and is not meant asvalidation that the material is truly random distributed.

The intergrowth of AEI/CHA is said to produce diffraction peaks at thefollowing 2-theta (2θ) positions: 9.5-9.7, 12.9-13.1, 14.0-14.2,16.1-16.3, 16.9-17.1, 19.1-19.3, 20.7-20.9, 21.3-21.5, 25.9-26.3 and30.9-31.2, FIG. 4. The AEI-CHA intergrowth has peaks characteristic ofan AEI structure type however the split peaks of pure AEI centered at17.2° 2θ have been replaced in the intergrowth by the broad peak centerat 17.1° 2θ. In addition the peaks associated with pure CHA at 17.8° and24.8° 2θ are no longer detected in the intergrowth AEI-CHA material.FIG. 5 shows the simulated diffraction produced by DIFFaX and theintergrowth AEI-CHA material. The simulated AEI/CHA ratios are asfollows: AEI-0/CHA-100, AEI-10/CHA-90, AEI-20/CHA-80, AEI-30/CHA-70,AEI-40/CHA-60, AEI-50/CHA-50, AEI-60/CHA-40, AEI-70/CHA-30,AEI-80/CHA-20, AEI-90/CHA-10 and AEI-100/CHA-0. All simulated patternswere scaled in intensity to the peak centered at 20.8 of the intergrowthAEI-CHA sample. The scaling of the simulated diffraction patterns allowsfor comparison between the various diffraction patterns.

By way of the comparison between the DIFFaX simulated diffractionpatterns and the intergrowth AEI-CHA sample it is possible to determinethe ratio of AEI-CHA in the sample. DIFFaX analysis indicated that theintergrowth AEI-CHA sample is of the ratio AEI-10/CHA90. The intergrowthAEI-CHA is characterized by the absence of any peak in the 9.8-12.0 2θ,shown in FIG. 6, and the absence of any broad peak centered at 16.9 2θ,shown in FIG. 7. An AEI-10/CHA-90 is also distinguished by the presenceof a broad peak centered at 17.9° 2θ shown in FIG. 8.

Copper was added to the 10:90 AEI/CHA intergrowth by a standardtechnique to produce a metal-loaded molecular sieve having about 1.8weight percent copper (based on the total weight of the molecularsieve).

Example 2 NO_(x) Performance of Copper-loaded AEI/CHA IntergrowthMolecular Sieves

The copper-loaded 10:90 AEI/CHA intergrowth sample was hydrothermallyaged for 72 hours at 700° C. The aged material was then applied as awashcoat to a monolith honeycomb core and tested using a SyntheticCatalyst Activity Test (SCAT) rig. The testing was performed undersimulated diesel exhaust gas conditions, namely exposing the catalyst toa gas at a space velocity of 50,000/hour, wherein the gas compositionwas about 350 ppm NH₃ and NO, about 14 weight % O₂, about 4.5 weight %H₂O, and about 5 weight % CO₂ in N₂. The test temperature ranged from200 to 450° C.

The sample was tested to determine its capacity for NO_(x) conversion(e.g. into N2 and O2) as a function of temperature. The results areshown in FIG. 9.

For comparison, a sample having only a CHA framework was also tested.The comparative sample was loaded with a similar amount of copper,underwent similar hydrothermal aging, and was tested using the SCAT rigunder similar conditions. The comparative data is also shown in FIG. 9.

What is claimed is:
 1. A catalyst for selective catalytic reduction ofNO_(x) comprising: a. one or more transition metals selected from thegroup consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd,Ag, In, Sn, Re, Ir, Pt, and mixtures thereof, and b. a supportcomprising a molecular sieve having at least one intergrowth phaseconsisting of an aluminosilicate, a silico-aluminophosphate, oraluminosilicate/silico-aluminophosphate combination having two differentsmall-pore, three-dimensional framework structures, wherein the firstframework structure is AEI and the second framework structure is CHA,wherein each framework structure in said intergrowth has a maximum ofeight ring members, wherein the one or more transition metals aredisposed inside the pores of the molecular sieve, on the externalsurface of the molecular sieve, or both inside the pores and on theexternal surface of the molecular sieve, and wherein said transitionmetal is present in an amount of about 0.01 to about 6 weight percent,based on the total weight of the molecular sieve.
 2. The catalyst ofclaim 1, wherein said intergrowth phase consists essentially of a firstsmall-pore, three-dimensional framework structure and a secondsmall-pore, three-dimensional framework structure, wherein said firstand second framework structures are present in a mole ratio of saidfirst framework structure to said second framework structure of about1:99 to about 99:1.
 3. The catalyst of claim 1, wherein said supportcomprises one aluminosilicate and one or more silico-aluminophosphates.4. The catalyst of claim 1, wherein said molecular sieve comprises anintergrowth of a first material selected from the group consisting ofSAPO-34, SSZ-13, SAPO-47, CAL-1, SSZ-62, and ZYT-6, and a secondmaterial selected from the group consisting of SAPO-18, SIZ-8, andSSZ-39.
 5. The catalyst of claim 1, wherein said first and secondframework structures are silico-aluminophosphates.
 6. The catalyst ofclaim 5, wherein said mole ratio is about 1:99 to about 50:50.
 7. Thecatalyst of claim 6, wherein said mole ratio is about 5:95 to about20:80.
 8. The catalyst of claim 5, wherein said molecular sieve is aSAPO-18/SAPO-34 intergrowth.
 9. The catalyst of claim 8, wherein saidmole ratio is about 1:99 to about 50:50.
 10. The catalyst of claim 8,wherein said mole ratio is about 5:95 to about 15:85.
 11. The catalystof claim 1, wherein said transition metal is selected from the groupconsisting of Cu, Fe, Co, Pt, and Mn.
 12. The catalyst of claim 1,wherein said transition metal is Cu.
 13. The catalyst of claim 5,wherein said transition metal is present in an amount of about 1 toabout 3 weight percent based on the total weight of the molecular sieve,and is selected from the group consisting of Cu, Fe, Co, Pt, and Mn. 14.The catalyst of claim 13, wherein said transition metal is selected fromthe group consisting of Cu and Fe.
 15. The catalyst of claim 9, whereinsaid transition metal is present in an amount of about 1 to about 3weight percent based on the total weight of the molecular sieve, and isselected from the group consisting of Cu, Fe, Co, Pt, and Mn.
 16. Thecatalyst of claim 1, wherein said transition metal is Cu and is presentin an amount of about 1.5 to about 2.5 weight percent based on the totalweight of the support, and wherein said support comprises an intergrowthof SAPO-18 and SAPO-34 in a mole ratio of SAPO-18 to SAPO-34 of about5:95 to about 15:85.
 17. A catalyst composition comprising: a. asupported metal catalyst comprising: i. one or more transition metalsselected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn,Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir, Pt, and mixtures thereof, andii. a support comprising a molecular sieve having at least oneintergrowth phase consisting of an aluminosilicate, asilico-aluminophosphate, or aluminosilicate/silico-aluminophosphatecombination having two different small-pore, three-dimensional frameworkstructures, wherein the first framework structure is AEI and the secondframework structure is CHA, wherein each framework structure in saidintergrowth has a maximum of eight ring members, wherein the one or moretransition metals are disposed inside the pores of the molecular sieve,on the external surface of the molecular sieve, or both inside the poresand on the external surface of the molecular sieve, and wherein saidtransition metal is present in an amount of about 0.01 to about 6 weightpercent, based on the total weight of the molecular sieve; and b. abinder selected from the group consisting of TiO₂, ZrO₂, SnO₂, CeO₂,alumina, silica, non molecular sieve silica-alumina, a naturallyoccurring clay, or mixtures thereof, wherein said supported metalcatalyst and said binder are combined to form a washcoat.
 18. Thecatalyst composition of claim 17, wherein said binder is selected fromthe group consisting of TiO₂, ZrO₂, SnO₂, and CeO₂.
 19. The catalystcomposition of claim 1, wherein said first and second frameworkstructures are aluminosilicates.
 20. The catalyst of claim 19, whereinsaid mole ratio is about 1:99 to about 50:50.
 21. The catalyst of claim20, wherein said mole ratio is about 5:95 to about 20:80.
 22. Thecatalyst of claim 20, wherein said molecular sieve is an SSZ-13/SSZ-39intergrowth.
 23. The catalyst of claim 22, wherein said transition metalis selected from the group consisting of Cu, Fe, Co, Pt, and Mn.
 24. Thecatalyst of claim 23, wherein said transition metal is Cu.
 25. Thecatalyst of claim 23, wherein said transition metal is present in anamount of about 1 to about 3 weight percent based on the total weight ofthe molecular sieve.